Packaging spool and process for producing same

ABSTRACT

A reel or spool package has opposing sidewalls or flanges formed of the specified or appropriate substrate and connected by a core formed of a flowable material which sets or cures to harden, such as a two part expandable polyurethane foam. The foam is applied into a partition, which may be a paper ring, by an injection and metering device. The chemistry of the flowable material may be altered to change density, rigidity and flexibility as required by package stresses. The polyurethane foam is an effective adhesive medium, thereby forming the core and connecting the sidewalls to form the package.

FIELD OF THE INVENTION

This invention relates to packaging materials generally, and is morespecifically related to reels or spools for packaging.

BACKGROUND OF THE INVENTION

Reel packages and spool packages are used for the packaging of productswhich are produced in a continuous and connected manner and are packagedin large number or high count continuous lengths for long run use,including automated use. These products are typically packaged in a“ribbon wound” (layer on layer) or convolute manner on a central core ofa size closely matching the width of the manufactured product, so thatthe user of the product may unwind the product in an orderly, controlledmanner for use or installation in other products. Products which arepackaged on reels and spools are made of a wide variety of raw materialsincluding metals, plastics, textiles and other products. The stiffnessof some continuous products is such that the package must have a corewith a large circumference (12 to 20″) to prevent undesired curling orbending of the manufactured product. Additionally, packages for theseproducts have sidewalls or flanges which act as retainers to keep theproduct from slipping off and becoming twisted, bent, damaged ordifficult or impossible to use. The sidewalls for larger reels used forrelatively rigid products range in size from 20″ to 48″, and are made ofcorrugated board, solid fibreboard, Masonite, plastic and plywood. Whilethere are technical differences between spools and reels as these termsare used in the art, the term “reel” is used herein to indicate reelsand spools used for packaging.

The cores of prior art reels are made of a number of substrates such aspre-formed and pre-cut styrofoam discs, or pressed wood, or plywooddiscs. Another embodiment employs rings of paper tubing cut frompre-made large diameter spiral or convolute paper tubes of a size orwidth which very nearly matches the width of the product being packaged.The sidewalls or flanges are then attached or fastened in a manner whichprotects the product from external damage, confines the product tominimal sidewise movement, and keeps the product wound in a single widthconvolute package, thereby allowing for orderly unwinding of the productby the user.

The methods employed in the prior art for joining sidewalls or flangesto cores are varied. Since some of the cores are discs with solid sides(such as styrofoam or pressed wood), adhesives are applied to thesesides and the sidewalls of paper and corrugated board are brought intocontact and unitized by the curing of the adhesive.

Other packages are of such large diameter that factors such as weightand cost make solid cores impractical. In such cases, cores are formedof paper rings of appropriate diameter and face width (matching theproduct to be wound) which are centered on sidewalls with holes punchedto accept flat head threaded bolts of a length appropriate to the widthof the product (with allowance for the thickness of the sidewallsubstrates). The bolt holes are positioned in close proximity to therings, so that when they are tightened, they eliminate, or minimize,rotation of the ring. The second sidewall is positioned, and bolts arepressed through both sidewalls, and capped head or “T” nuts are attachedto the bolts and tightened, creating a circular package or reelcustomized to the products width and load area. The load area is thearea from the ring or core to the outside diameter of the flange orsidewall is the load area.

The sidewalls or flanges often have punches or apertures for differentfunctions positioned on its face such as:

-   -   1. A center or arbor hole for mounting on an axis or rod for        smooth “take up” or “let off” of the continuous product.    -   2. A drive hole to accept a pin which will, when a rotational        force is applied, turn the package and thereby wind or “take up”        the product as it is produced. (This arbor and drive hole        configuration has become largely standardized and has a fixed        central location)    -   3. Small apertures for inspection, product access and handling,        which have no meaningful structural significance.

SUMMARY OF THE INVENTION

The present invention is an improvement of reel or spool packages. Thepackage of the present invention comprises opposing sidewalls or flangesformed of the specified or appropriate substrate which are connected bya core. The core is formed by a partition which acts as a mold, such asa simplified paper ring, filled with a flowable material which hardens.The flowable material may be a two part expandable polyurethane foamwhich is applied into the partition by a metering and injection device.The chemistry of the foam formulation may be altered to change density,rigidity and flexibility as required by package stresses. The foam is avery aggressive and effective adhesive medium, which forms the corewhile connecting the sidewalls to form the package.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top, plan view of a reel used for packaging.

FIG. 2 is a sectioned view of a reel for packaging.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The reel package of the present invention comprises opposing sidewalls2,4 or flanges formed of the specified or appropriate substrate. FIG. 1.The sidewalls are connected by a core 6 formed of polyurethane. The coreis formed or molded by preparing a partition, which may be a ring 8. Thering may be made of paper or other suitable material, which is filledwith a flowable material 10, and acts as a mold, and forms the flowablematerial.

The flowable material is a liquid or semi-liquid material, which willharden or set to form a core. The flowable material also acts asadhesive to connect the sidewalls to the core.

The flowable material is preferred to be comprised of two-partexpandable polyurethane foam. Polyurethanes are formed by isocyanates,which are reacted with agents having a hydroxyl group, such as polyols.These materials may be produced as foam which expands as it isdispensed. The foam is delivered into a defined void in a metereddosage. The foam fills the void, and the reaction of the componentscauses the foam to set and become solid in the shape of the void. Thechemistry of the foam formulation may be altered to change density,rigidity and flexibility as required by package stresses. The expandedfoam is a very aggressive and effective adhesive medium. As the foamcures it adheres to each of the sidewalls, it performs the dual functionof forming the core and connecting the sidewalls to form the completedreel, and no mechanical fasteners are required.

A partition accepts the foam therein and molds the foam to form thecore. The preferred material for the partition is a ring formed ofpaper. A paper ring is easily and inexpensively formed. The foam isapplied into the paper ring by an injection device, which meters thefoam to be injected. Upon injection into paper ring, the wet foam bondsto the sidewalls. The foam reacts and hardens to form the core after anexothermic reaction of short duration. Normally, it is unnecessary toremove the paper ring after the foam sets.

A simple frame, sized to handle multiple sidewall diameters, fitted withmechanically retractable dowels centrally positioned to form the arborholes and drive holes may be used as an assembly fixture for thepackage. Two sidewalls, prepared with appropriate apertures, includingany required arbor or drive holes 12, are sized to slip over the dowels.Sidewall 2 is positioned in the assembly fixture over the retractabledowels. A paper ring 6 of appropriate width and diameter is positionedand mechanically centered on the sidewall by position guides. Acontrolled amount of the specially formulated two part expandablepolyurethane foam is injected into to the void 10 created by the outer(paper ring) and the center dowel. The second or top sidewall 4 is putin place as the foam begins to expand and fill the void, which becomes aclosed compartment created by the positioning of the second sidewall orflange.

The foam expands to the limits of the compartment or void formed by thepaper ring. In the process, the foam bonds all of the substrates orcomponents into a single, rigid, lightweight package of a size andstrength required for the application. The dowels are retracted leavingthe arbor and drive holes clear and in proper position.

For reels or packages which require large diameter cores and wideseparation of the sidewalls or flanges, the amount of foam used can bereduced by a second ring 14 of a smaller diameter, but which matches thewidth or face dimension of the outer ring. The second ring is usuallyplaced concentrically with the first ring. A compartment is formedbetween the top and bottom sidewalls and the two rings into which thefoam is dispensed. Chemical variation of the density of the foam mixallows the strength characteristics to be adjusted to compensate for thereduced area of adhesion. The use of two rings to create a compartmentreduces the amount of polyurethane used to fill a void and create abond. Other shaped materials are also effective in partitioning a void,or occupying space in the void, to achieve the similar results.

For reels with relatively small cores only a single paper ring ofappropriate diameter will normally be used. An assembly fixture with thecommercially available foam injection device assists in assembly andbonding. For maximum size capability, a yoke positioned between thesidewall flanges and configured (or vacuum fitted) to position a heavygauge paper strip in a circle around the center at the appropriate sizeposition is sufficient to act as a barrier to the foaming agent, andeffectively create the core of the proper size.

Spools and the large diameter reels mentioned earlier are of the samefamily of circular packaging. The invention works well with reelpackages having diameters of 20 inches to 48 inches, and is particularlycost effective with regard to such relatively large spools. Otherapplications of the process of the invention lend themselves to thedramatic cost savings in eliminating components and complexity ofassembly. For example, plywood sided reels or spools which currently usethe “Bolt-Thru” method of assembly may be formed by the method herein.The formulations achievable with the foam and the light wallpaper tubesto compartmentalize the application are very effective low costreplacements for the cores and assembly processes of the prior art,without changing the plywood used as the sidewall medium. The bondstrength and variable density features are ideal for many heavy-dutyapplications.

Retail ribbon spools are another area of potential application. Thestress requirements are very low and the paper tubes currently used asthe core material represent a major portion of the components cost. Thereplacement of the tube with a simple paper barrier compartment and foambonding is simpler and less expensive.

Since the polyurethane foam is a highly effective bonding agent, plasticspools which require solvent bonding and complex tooling to impartstrength and gain dimensional integrity are unnecessary. The use ofsimplified flanges bonded to a high strength core according to thepresent invention is an effective replacement. The elimination ofharmful solvents is considered a benefit to the safety of the workplace. The urethane foam is a safe bonding agent, and has an enviablerecord in industrial applications.

1. A method of producing a reel for packaging, comprising: a. forming afirst sidewall and a second sidewall; b. placing a partition having avoid therein of a generally circular cross section, adjacent to, andgenerally concentrically with, said first sidewall; c. filling said voidof said partition with a flowable material which will form into a solidcore and which will adhere to said first sidewall and said secondsidewall; d. placing said second sidewall in a generally parallel andconcentric relationship with said first sidewall and against saidpartition, wherein said flowable material adheres to said first sidewalland to said second sidewall and forms a solid core.
 2. The productproduced by the method of claim 1.